Why is functions.firestore.v2.document Undefined in My Firebase Cloud Functions?

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I'm encountering a persistent error: "TypeError: Cannot read properties of undefined (reading 'document')" when deploying my Firebase Cloud Functions. This error arises when defining a Firestore trigger using functions.firestore.v2.document(...), even though all import statements and initialization steps seem correct.

Code:

JAVASCRIPT
const functions = require("firebase-functions");
const admin = require("firebase-admin");
const axios = require("axios");
const { FieldValue } = require('firebase-admin/firestore');

admin.initializeApp();
const db = admin.firestore();

exports.rahh = functions.firestore.v2.document("user/{userId}").onCreate(async (event) => {
    // ... (My function logic here - fetching data from Google People API) ...
});

Error Message:

TypeError: Cannot read properties of undefined (reading 'document')
at Object. (C:\path\to\my\functions\index.js:9:39)
... (Rest of the stack trace) ...

Problem:

The firestore property on the imported functions object appears undefined when accessing functions.firestore.v2.document(...). This occurs despite having correct import statements and initializing the Firebase Admin SDK with admin.initializeApp();.

What I've Tried:

Emulator Reset: firebase emulators:stop, firebase emulators:clear, firebase emulators:start --only functions
Node Version: Switched to Node 18 (using nvm).
Emulator Run: The function works perfectly when running on the emulator.
Package Lock File: Removed package-lock.json and node_modules, then ran npm install
Global Firebase CLI: Updated with npm install -g firebase-tools
Simplified index.js: Created a minimal index.js with a simple HTTPS function and it worked!
Checked main in package.json: The main field is correctly set to index.js.
Double-checked for typos: Confirmed no typos in imports or function calls.
Used a basic text editor: Edited index.js in Notepad to rule out IDE issues.

package.json:

JSON
{
  "name": "functions",
  "description": "Cloud Functions for Firebase",
  "scripts": { /* ... */ },
  "engines": { "node": "18" },
  "main": "index.js",
  "dependencies": {
    "axios": "^1.7.9",
    "firebase": "^11.2.0", // Firebase client SDK (might not be needed in functions)
    "firebase-admin": "^13.0.2",
    "firebase-functions": "^6.3.1"
  },
  "devDependencies": { /* ... */ },
  "private": true
}

Firebase CLI Version: 13.29.3

The fact that a new project works suggests a configuration issue I have yet to identify. What could be causing this "undefined" error even with correct imports and thorough troubleshooting?

Comments 0

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Answers 2

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2 Answers

Answer by StackOverflow TychoAI Agent • 1 month ago

The error indicates that the v2 Firestore trigger API isn’t available on your imported functions object. In other words, functions.firestore.v2 is undefined because your current setup isn’t “seeing” the new v2 API.

There are two common resolutions:

Upgrade Your firebase-functions Package
Make sure you have a version of the firebase-functions SDK that supports Cloud Functions v2 triggers. If your current version does not include the v2 API for Firestore, update your dependency (for example, using a recent version where v2 triggers are available).

Use the New Import Path
The v2 Firestore triggers can be imported from their own module instead of accessing them off the functions object. For example, replace:

JAVASCRIPT
exports.rahh = functions.firestore.v2.document("user/{userId}").onCreate(async (event) => {
    // Your function logic
});

with

JAVASCRIPT
const { onDocumentCreated } = require("firebase-functions/v2/firestore");

exports.rahh = onDocumentCreated("user/{userId}", async (event) => {
    // Your function logic
});

Using this dedicated import path ensures that you’re accessing the v2 API correctly.

Choose the approach that best fits your needs. If you’d like to keep your current project structure without changing import paths, upgrading the firebase-functions dependency is the way to go. Otherwise, using the new module import (as shown) is the recommended method to work with v2 triggers directly.

These steps should resolve the "TypeError: Cannot read properties of undefined (reading 'document')" error.

Tycho is an AI agent, that grounds responses in various sources like documentation, code bases, live discussions, and relevant posts. Want to chat privately with Tycho?

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Answer by AsteroidScout452 • 1 month ago

You're trying to use v2 Cloud Functions, but using the v1 syntax.

In the documentation on extending Firestore with Cloud Functions (2nd gen) it shows this:

JAVASCRIPT
import {  
  onDocumentWritten,  
  onDocumentCreated,  
  onDocumentUpdated,  
  onDocumentDeleted,  
  Change,  
  FirestoreEvent  
} from "firebase-functions/v2/firestore";

exports.myfunction = onDocumentWritten("my-collection/{docId}", (event) => {  
   /* ... */  
});

For v1/gen2 you'll want to model after that, with a top-level onDocumentCreated import rather than the namespaced syntax.

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Why is functions.firestore.v2.document Undefined in My Firebase Cloud Functions?

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